1. Field of the Invention
The invention relates to an optical imaging device having at least one optical element which is provided with an outer frame, an inner ring in which the optical element is mounted, and a manipulator instrument having at least one actuator. The invention furthermore relates to a projection objective for microlithography.
2. Description of the Related Art
DE 199 01 295 A1 discloses an optical imaging device having an optical element, the optical element, e.g. a lens, being mounted in an inner ring which is connected to an outer frame by leaf springs and setting levers. A manipulator instrument for displacing the optical element is designed so that the articulations employed serve as a manipulator instrument with adjusting components between the inner ring and the outer frame. Adjusting screws engage on the adjusting components as actuators for displacing the optical element. Adjustment of the adjusting screws leads to a displacement of the inner ring relative to the outer frame.
DE 100 51 706 A1 furthermore discloses a device for mounting an optical element, the device being provided with an inner frame and an outer frame. The inner frame is connected to the outer frame by three solid-state articulations arranged distributed over the circumference, with actuators which can displace the inner frame engaging on the solid-state articulations.
These documents disclose that it is possible to induce forces and moments in the inner ring by direct linkage of the outer frame to the inner ring, although these can cause a deformation of the inner ring and therefore a deformation of the lens. Parasitic effects can therefore act on the lens, such as tilting, astigmatism and other higher-order deformations.